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Message-ID: <20241021151257.102296-3-bigeasy@linutronix.de>
Date: Mon, 21 Oct 2024 17:08:41 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: linux-trace-kernel@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Peter Zijlstra <peterz@...radead.org>,
tglx@...utronix.de,
mingo@...nel.org,
juri.lelli@...hat.com,
vincent.guittot@...aro.org,
dietmar.eggemann@....com,
rostedt@...dmis.org,
bsegall@...gle.com,
mgorman@...e.de,
vschneid@...hat.com,
ankur.a.arora@...cle.com,
efault@....de,
Masami Hiramatsu <mhiramat@...nel.org>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH v2 2/3] tracing: Record task flag NEED_RESCHED_LAZY.
From: Thomas Gleixner <tglx@...utronix.de>
The scheduler added NEED_RESCHED_LAZY scheduling. Record this state as
part of trace flags and expose it in the need_resched field.
Record and expose NEED_RESCHED_LAZY.
[bigeasy: Commit description, documentation bits.]
Reviewed-by: Ankur Arora <ankur.a.arora@...cle.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@...dmis.org>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
Documentation/trace/ftrace.rst | 4 ++++
include/linux/trace_events.h | 1 +
kernel/trace/trace.c | 2 ++
kernel/trace/trace_output.c | 14 +++++++++++++-
4 files changed, 20 insertions(+), 1 deletion(-)
--- a/Documentation/trace/ftrace.rst
+++ b/Documentation/trace/ftrace.rst
@@ -1036,9 +1036,13 @@ explains which is which.
be printed here.
need-resched:
+ - 'B' all, TIF_NEED_RESCHED, PREEMPT_NEED_RESCHED and TIF_RESCHED_LAZY is set,
- 'N' both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED is set,
- 'n' only TIF_NEED_RESCHED is set,
- 'p' only PREEMPT_NEED_RESCHED is set,
+ - 'L' borg PREEMPT_NEED_RESCHED and TIF_RESCHED_LAZY is set,
+ - 'b' borg TIF_NEED_RESCHED and TIF_RESCHED_LAZY is set,
+ - 'l' only TIF_RESCHED_LAZY is set
- '.' otherwise.
hardirq/softirq:
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -185,6 +185,7 @@ unsigned int tracing_gen_ctx_irq_test(un
enum trace_flag_type {
TRACE_FLAG_IRQS_OFF = 0x01,
TRACE_FLAG_NEED_RESCHED = 0x02,
+ TRACE_FLAG_NEED_RESCHED_LAZY = 0x04,
TRACE_FLAG_HARDIRQ = 0x08,
TRACE_FLAG_SOFTIRQ = 0x10,
TRACE_FLAG_PREEMPT_RESCHED = 0x20,
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2544,6 +2544,8 @@ unsigned int tracing_gen_ctx_irq_test(un
trace_flags |= TRACE_FLAG_NEED_RESCHED;
if (test_preempt_need_resched())
trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
+ if (IS_ENABLED(CONFIG_ARCH_HAS_PREEMPT_LAZY) && tif_test_bit(TIF_NEED_RESCHED_LAZY))
+ trace_flags |= TRACE_FLAG_NEED_RESCHED_LAZY;
return (trace_flags << 16) | (min_t(unsigned int, pc & 0xff, 0xf)) |
(min_t(unsigned int, migration_disable_value(), 0xf)) << 4;
}
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -463,17 +463,29 @@ int trace_print_lat_fmt(struct trace_seq
!IS_ENABLED(CONFIG_TRACE_IRQFLAGS_SUPPORT) ? 'X' :
'.';
- switch (entry->flags & (TRACE_FLAG_NEED_RESCHED |
+ switch (entry->flags & (TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY |
TRACE_FLAG_PREEMPT_RESCHED)) {
+ case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED:
+ need_resched = 'B';
+ break;
case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_PREEMPT_RESCHED:
need_resched = 'N';
break;
+ case TRACE_FLAG_NEED_RESCHED_LAZY | TRACE_FLAG_PREEMPT_RESCHED:
+ need_resched = 'L';
+ break;
+ case TRACE_FLAG_NEED_RESCHED | TRACE_FLAG_NEED_RESCHED_LAZY:
+ need_resched = 'b';
+ break;
case TRACE_FLAG_NEED_RESCHED:
need_resched = 'n';
break;
case TRACE_FLAG_PREEMPT_RESCHED:
need_resched = 'p';
break;
+ case TRACE_FLAG_NEED_RESCHED_LAZY:
+ need_resched = 'l';
+ break;
default:
need_resched = '.';
break;
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